(Not Applicable)
It is conventional in decision analysis to weigh a variety of diverse factors and combine these factors either directly or through proportional logic to derive metrics. For example, a student""s grade may be based 20% on homework scores, 10% on class participation, 10% on classroom behavior, and 60% on test scores. Such a grade would be                     G        =                              ∑            i            4                    ⁢                                    w              i                        ⁢                          x              i                                                  1      
where wi=the individual weights; xi=the individual grades; and             ∑      l      n        ⁢          w      i        =  1.
This linear analysis has been used for many years in education and many other fields; however, it and other known analysis systems may not be satisfactory for weighing factors that are uncertain and which do not combine linearly or independently. Surety analysis and the associated decision analysis for such conventional systems are basically applicable to only experience-measurable or physical-model-derived data. However, most practical analyses, including high-consequence system surety analysis, must also utilize subjectivity.
It is a challenging task to systematically (preferably mathematically) assess subjective factors such as organizational factors as to their effects on system operation. Furthermore, these are generally latent factors that influence critical system operation over time. For instance, if a grade is supposed to measure the student""s knowledge in a subject, other factors relating to the school, the teacher, the administration, and the student""s home life also have an effect on the student""s knowledge, but these factors are not accounted for in the traditional system.
There has been considerable prior effort on analytically incorporating engineering judgment into analysis systems. For example, Dempster-Shafer theory establishes a framework in which frequentist probability and Bayesian incorporation of new data are subsets. Although these methodologies both allow judgment, neither derives results that can explicitly indicate the relative amounts of subjective judgment and measurable data in the results.
For example, the safety status of an airline operation might depend on measuring factors such as the implications of accident/incident statistics, maintenance personnel/pilot competence and experience, scheduling pressures, and the safety xe2x80x9cculturexe2x80x9d of the organization. Many of the potential metrics on such parameters are difficult (and generally uncertain) to determine. A top-down analytical approach requires more than individual parameter assessment which is used in some conventional tabular schemes. Furthermore, aggregation of the parameters into an overall metric requires a methodology that can account for nonlinearities and dependence. Twice as many attributes is unlikely to be twice as beneficial, and scheduling pressures could influence accident/incident statistics.
It is an object of this invention is to provide a new risk management decision-aid methodology.
It is also an object of this invention to aggregate data that are inputs (both objective and subjective) to each subsystem by a xe2x80x9csoft aggregationxe2x80x9d process.
It is a further object to track uncertainty whereby inputs may be entered with uncertainty measures and output uncertainty may be correspondingly determined.
It is another object to provide a technique to account for dependence between or among inputs (which is by far the most common case as opposed to independent inputs).
It is also an object of the invention to account for xe2x80x9cimportancexe2x80x9d (contribution of each input to the output value(s)) and xe2x80x9csensitivityxe2x80x9d (potential for improvement in the output due to each input(s)).
And it is an object of the invention to be able to determine xe2x80x9ctrendsxe2x80x9d for each input and output over time.
It is also an object of this invention to display inputs as they are entered, outputs as they are aggregated for overall contribution or xe2x80x9cearly alerts,xe2x80x9d in a manner that is unusually natural for humans to understand and work with (instrumentation-like displays portrayed on a computer screen)
To achieve the foregoing and other objects, and in accordance with the purpose of the present invention, as embodied and broadly described herein, the present invention may comprise a method of nonlinear decision analysis, comprising providing a plurality of inputs having either positive or negative values, and determining an output representative of a decision as a function of the inputs, where the output approaches a first value asymptotically as the value of positive inputs increases, and approaches a second value asymptotically as the value of negative inputs increases. The invention further includes instrumentation-like gage displays (giving a human-friendly interface and display of uncertainty range) for displaying inputs and outputs, an architecture of subsystem modules that are interconnected to reflect latent effects, and a xe2x80x9csoft aggregationxe2x80x9d combination of input data to reflect nonlinear accumulation of effects.
Additional objects, advantages, and novel features of the invention will become apparent to those skilled in the art upon examination of the following description or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.